The use of power tools to perform operations such as cutting, sawing, drilling, etc. on a workpiece is often problematic when the workpiece is not securely held in place, particularly with regard to safety and accuracy. For example, cutting aluminum picture frame mouldings at sharp angles such as 45.degree. with a power miter saw can produce pulling forces on the mouldings which often make it very difficult for an operator to safely hold the moulding by hand and still get an accurate cut. This problem exists since cutting a workpiece at a 45.degree. angle with a miter saw tends to pull the material towards the saw blade. Especially if the workpiece being cut is rather small, for example three inches long, an operator's hand may need to be placed dangerously close to the blade, which introduces unacceptably hazardous conditions for the operator.
Various clamping mechanisms are available to assist an operator in securing workpieces while these workpieces are operated upon by a power tool. However, many of these available clamping mechanisms suffer from a number of drawbacks which diminish their performance, particularly with regard to clamping small workpieces.
For example, popular standard power miter saws such as the Ryobi Model TS 254 power miter saw have warning lines cast into the base of the saw table warning users not to place their fingers closer than about 6 inches from the saw blade. This saw has holes cast into the base to accept screw clamps that are an accessory for the saw. However, these holes are about 7 inches from the saw blade, so the clamp will not work on very small pieces. The Ryobi clamp works in a straight line from the front to the back of the saw, and consequently, it cannot be placed close to the saw blade or it will be sawed into when the saw is turned to an angle such as 45.degree.. The Ryobi clamps also do not work well for clamping many of the small aluminum extrusions that picture framers use. Also, the clamp frequently rides upward as it is being closed on these low profile mouldings, and it is therefore difficult to clamp these mouldings even when the pieces required are long enough for the clamp. Other brands of miter saws have problems similar to the Ryobi miter saw with regard to clamping and cutting very small pieces of material.
Power miter saws, among others, provide unique difficulties in clamping in that these saws are capable of rotating about an axis perpendicular to a work surface thereof (typically .+-.45.degree.). Since these saws are required to rotate, any clamps therefor must stay clear of the saw blade and the saw adjusting handle that protrudes from the front of the saw regardless of the rotational position of the saw. While clamps can also be operated from the rear of the saw, a similar problem exists insofar as the rear of the saw includes a swing arm that supports the saw and the motor and rotates concurrently therewith. Conventional clamps which are used on these types of saws must necessarily have sufficient clearance from the saw to enable a free range of rotation for the saw. As discussed above, this limits the applicability of these clamps for use with smaller workpieces which must be secured, if at all, closer to the blade of the saw.
Consequently, a need exists in the art for a clamping mechanism which is capable of supporting a workpiece relatively close to a power tool workhead such as a power miter saw, but which will not interfere with or otherwise obstruct the power tool. Further, as discussed above, a need exists for a clamping mechanism which is capable of adequately resisting the pulling forces applied by a power tool during operation, in order to provide greater accuracy and additional safety for an operator.